ferment vs irritation

ferment

noun
  • A state of agitation or of turbulent change. 

  • Something, such as a yeast or barm, that causes fermentation. 

  • A gentle internal motion of the constituent parts of a fluid; fermentation. 

  • A catalyst. 

verb
  • To stir up, agitate, cause unrest or excitement in. 

  • To react, using fermentation; especially to produce alcohol by aging or by allowing yeast to act on sugars; to brew. 

irritation

noun
  • The state of being irritated 

  • A things or person that annoys 

  • A condition of morbid excitability or oversensitiveness of an organ or part of the body; a state in which the application of ordinary stimuli produces pain or excessive or vitiated action. 

  • The act of irritating or annoying 

  • a state of inflammation or painful reaction to allergy or cell-lining damage. 

How often have the words ferment and irritation occurred in a corpus of books? (source: Google Ngram Viewer )